There is a need for prepreggable epoxy resin compositions for use in continuous composite fabrication processes. While a large number of epoxy resin formulations are known in the art, such formulations do not have a desirable combination of both pre- and post-pultrusion properties, which would allow the resin to exit a pultrusion die in a "postformable" condition having the ability to flow sufficiently to form a slightly different shape, e.g., including with a slight twist or taper, when placed in a heated mold and then form a thermoplastic solid when quenched at room temperature. Thus, although numerous curing agents and other epoxy resin additives are known, the properties of an individual additive material convey various advantageous and disadvantageous properties to an epoxy resin formulation and even combinations of such additive materials have not filled the needs for an epoxy resin formulation suitable for the continuous composite fabrication processes discussed above.